The Pentagon will send hundreds of additional spies overseas as part of an ambitious plan to assemble an espionage network that rivals the CIA in size, U.S. officials said.

The project is aimed at transforming the Defense Intelligence Agency, which has been dominated for the past decade by the demands of two wars, into a spy service focused on emerging threats and more closely aligned with the CIA and elite military commando units.

When the expansion is complete, the DIA is expected to have as many as 1,600 “collectors” in positions around the world, an unprecedented total for an agency whose presence abroad numbered in the triple digits in recent years.

The total includes military attachés and others who do not work undercover. But U.S. officials said the growth will be driven over a five-year period by the deployment of a new generation of clandestine operatives. They will be trained by the CIA and often work with the U.S. Joint Special Operations Command, but they will get their spying assignments from the Department of Defense.